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Use of the Impella 2.5 in High-Risk Percutaneous Coronary Intervention Brenda McCulloch Crit Care Nurse 2011, 31:e1-e16. doi: 10.4037/ccn2011293 © 2011 American Association of Critical-Care Nurses Published online http://www.cconline.org Subscription Information http://ccn.aacnjournals.org/subscriptions Information for authors http://ccn.aacnjournals.org/misc/ifora.xhtml Submit Manuscript www.editorialmanager.com/ccn E-mail alerts http://ccn.aacnjournals.org/subscriptions/etoc.xhtml Critical Care Nurse is the official peer-reviewed clinical journal of the American Association ofCritical-Care Nurses, published bi-monthly by The InnoVision Group 101 Columbia, Aliso Viejo, CA 92656. Telephone: (800) 899-1712, (949) 362-2050, ext. 532. Fax: (949) 362-2049. Copyright © 2011 by AACN. All rights reserved. Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 Feature Use of the Impella 2.5 in High-Risk Percutaneous Coronary Intervention Brenda McCulloch, RN, MSN The Impella 2.5 is a percutaneously placed partial circulatory assist device that is increasingly being used in high-risk coronary interventional procedures to provide hemodynamic support. The Impella 2.5 is able to unload the left ventricle rapidly and effectively and increase cardiac output more than an intra-aortic balloon catheter can. Potential complications include bleeding, limb ischemia, hemolysis, and infection. One community hospital’s approach to establishing a multidisciplinary program for use of the Impella 2.5 is described. (Critical Care Nurse. 2011;31[1]:e1-e16) P atients who undergo highrisk percutaneous coronary intervention (PCI), such as procedures on friable saphenous vein grafts or the left main coronary artery, may have an intra-aortic balloon catheter placed if they require hemodynamic support during the procedure. Currently, the intra-aortic balloon pump (IABP) is the most commonly used device for circulatory support. A newer option that is now available for select patients is the Impella 2.5, a shortterm partial circulatory support device or percutaneous ventricular assist device (VAD). In this article, I discuss the Impella 2.5, review indications and contraindications for its use, delineate potential complications of the ©2011 American Association of CriticalCare Nurses doi: 10.4037/ccn2011293 e1 CriticalCareNurse OnlineNOW Impella 2.5, and discuss implications for nursing care for patients receiving extended support from an Impella 2.5. Additionally, I share our experiences as we developed our Impella program at our community hospital. Routine management of patients after PCI is not addressed. IABP therapy has been in use since the late 1960s and has been widely used in clinical practice since that time. The IABP decreases afterload, decreases myocardial oxygen consumption, increases coronary artery perfusion, and modestly enhances cardiac output.1,2 The IABP cannot provide total circulatory support. Patients must have some level of left ventricular function for an IABP to be effective. Optimal hemodynamic effect from the IABP is dependent on several factors, including the balloon’s position in the aorta, the blood displacement volume, the balloon diameter in relation to aortic diameter, the timing of balloon inflation in diastole and deflation in systole, and the patient’s own blood pressure and vascular resistance.3,4 The Impella 2.5 (Figure 1) aspirates up to 2.5 L/min of blood from the left ventricle and displaces it into the ascending aorta, rapidly unloading the left ventricle and increasing forward flow. It reduces myocardial oxygen consumption, improves mean arterial pressure, and reduces pulmonary capillary wedge pressure.2 The Impella provides a greater increase in cardiac output than the IABP provides. In one trial5 in which an IABP was compared with an Impella in cardiogenic shock patients, after 30 minutes of therapy, the cardiac index (calculated as cardiac output in liters per minute divided by body surface area in square meters) increased by 0.5 in the patients with the Impella compared with 0.1 in the patients with an IABP. Unlike the IABP, the Impella does not require timing, nor is a trigger from an electrocardiographic rhythm or arterial pressure needed (Table 1). The device received 510(k) clearance from the Food and Drug Administration in June 2008 for providing up to 6 hours of partial www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 cardiomyopathy with acute decompensation, postcardiotomy shock, off-pump coronary artery bypass grafting surgery, or heart transplant rejection and as a bridge to the next decision.9 Clinical Research and Registry Findings In Europe, the Impella 2.5 has been in wide use for several years.8,9 In the United States, several small Figure 1 Impella 2.5 cardiac assist device in left ventricle. trials5,6,9-12 have Image courtesy ABIOMED Inc, Danvers, Massachusetts. been completed or are underway circulatory support. In Europe, the to evaluate the Impella 2.5. Abiomed Impella 2.5 is approved for use up to has sponsored several of these trials, 5 days. Reports of longer duration including PROTECT I, PROTECT II, of therapy in both the United States RECOVER I, RECOVER II, and and Europe have been published.8,9 ISAR-SHOCK. The Impella 2.5 has been used The PROTECT I study was done for hemodynamic support during to assess the safety and efficacy of high-risk PCI and for hemodynamic device placement in patients undersupport of patients with myocardial going high-risk PCI.10 Twenty patients infarction complicated by cardiogenic were enrolled in that prospective, shock or ventricular septal defect, multicenter study. All had poor Author Brenda McCulloch is a cardiovascular clinical nurse specialist at Sutter Heart and Vascular Institute, Sutter Medical Center, Sacramento, California. Corresponding author: Brenda McCulloch, RN, MSN, Sutter Heart and Vascular Institute, Sutter Medical Center, 5301 F Street, Suite 304, Sacramento, CA 95819 (e-mail: [email protected]). To purchase electronic or print reprints, contact The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Phone, (800) 899-1712 or (949) 362-2050 (ext 532); fax, (949) 362-2049; e-mail, [email protected]. ventricular function (ejection fraction ≤35%) and had PCI on an unprotected left main coronary artery or the last remaining patent coronary artery or graft. The device was successfully placed in all patients, and the duration of support ranged from 0.4 to 2.5 hours. None of the patients had hemodynamic instability develop during the procedure. Two patients had transient hemolysis that was not clinically significant. Following this trial, the Impella 2.5 device received its 510(k) approval from the Food and Drug Administration. The ISAR-SHOCK trial was done to evaluate the safety and efficacy of the Impella 2.5 versus the IAPB in patients with cardiogenic shock due to acute myocardial infarction.5 Patients were randomized to support from an IABP (n=13) or an Impella (n=12). One patient died before implantation of a device. The trial’s primary end point of hemodynamic improvement was defined as improved cardiac index at 30 minutes after implantation. Improvements in cardiac index were significantly greater in the patients with the Impella than in patients with the IABP (P=.02). The patients’ diastolic pressure increased significantly more with Impella support than with IABP support (P=.002). Mean arterial pressure increased in patients with an Impella more than it increased in patients with an IABP, but the difference was not significant (P=.09). The use of inotropic agents and vasopressors was similar in both groups of patients. Serum level of lactate was lower in patients treated with the Impella. Hemolysis, as measured by the plasma level of free hemoglobin, was higher in patients treated with the Impella. www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e2 Table 1 Comparing traditional intra-aortic balloon therapy with Impella 2.5 percutaneous ventricular assist device Feature Intra-aortic balloon therapy6,7 Impella 2.5 Duration of use Short-term use: hours to days Approved by the Food and Drug Administration for use up to 6 hours; approved in Europe for up to 5 days How does it work? Blood volume displacement Requires cardiac rhythm or arterial pressure for trigger Requires intermittent timing to ensure optimal inflation and deflation of balloon Increases cardiac output more than an intra-aortic balloon pump does Works independently of cardiac rhythm or arterial pressure No timing required because it is continuous flow Physiological impact Decreases afterload Augments cardiac output modestly Moderate to severe aortic insufficiency Abdominal or aortic aneurysm Increases forward flow Unloads left ventricle Augments cardiac output Increases mean arterial pressure Contraindications Moderate to severe peripheral arterial disease Mechanical aortic valve Moderate to severe aortic diseease Left ventricular thrombus Moderate to severe peripheral arterial disease Cost $800-$1200 for cost of device and associated supplies plus cost of console $20 000-$25 000 for cost of device and associated supplies; console provided with catheter purchase Potential complications Limb ischemia Bleeding, hematoma at access site Vascular injury Embolization of thrombus or plaque Infection Balloon rupture Limb ischemia Bleeding, hematoma at access site Vascular injury Hemolysis Embolization of thrombus or plaque Infection Device failure More blood products were administered to patients treated with the Impella. Results from additional clinical trials are available (Table 2), but continuing clinical trials are essential to evaluate the effectiveness of the Impella 2.5 device in various subgroups. Device Design The Impella 2.5 catheter (Figure 2) contains a nonpulsatile microaxial continuous flow blood pump (Figure 3) that pulls blood from the left ventricle to the ascending aorta, creating increased forward flow and increased cardiac output. An axial pump is one that is made up of impellar blades, or rotors, that spin around a central shaft; the spinning of these blades is what moves blood through the device.13 The distal tip of pigtail curve is 6F in size (Figure 4). The Impella 2.5 e3 CriticalCareNurse OnlineNOW catheter shaft size is 9F and is 12F at its largest point, which is the microaxial blood pump. The Impella 2.5 catheter has 2 lumens. A tubing system called the Quick Set-Up has been developed for use in the catheterization laboratory. It is a single tubing system that bifurcates and connects to each port of the catheter. This arrangement allows rapid initial setup of the console so that support can be initiated quickly. When the Quick Set-Up is used, the 10% to 20% dextrose solution used to purge the motor is not heparinized. One lumen carries fluid to the impellar blades and continuously purges the motor to prevent the formation of thrombus. The proximal port of this lumen is yellow. The second lumen ends near the motor above the level of the aortic valve and is used to monitor aortic pressure. The console uses this pressure measurement to calculate the catheter’s position. The proximal port of this lumen is red. If the Impella remains in place for continued support after the PCI, the tubing system is changed to 2 separate systems. For continued use, the purge fluid is heparinized (50 units heparin per milliliter of fluid) and infused via an integrated infusion pump, the Braun Vista infusion pump (Figure 5). The typical infusion rate for the purge fluid is 7 to 20 mL/h. The second lumen of the Impella 2.5 is flushed with heparinized saline (500 mL normal saline with 1000 units heparin) by using regular (not infusion pump) intravenous tubing. The heparinized saline is placed in a pressure bag that is inflated to 300 mm Hg. Other www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 Table 2 Review of the research Study, year Sample size Purpose Findings Henriques et al,9 2006 To evaluate safety and fea- 19 consecutive patients undergoing sibility of using Impella high-risk PCI after percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction Remmelink et al,6 2007 Evaluate effects of left ventricular unloading by the Impella 2.5 on coronary hemodynamics 11 consecutive patients who underwent elective high-risk PCI Aortic and coronary pressures increased with Impella support (P = .001) Seyfarth et al,5 2008 ISAR–SHOCK, sponsored by Abiomed Evaluate safety and efficacy of Impella 2.5 compared with intraaortic balloon pump (IABP) in cardiogenic shock after acute myocardial infarction 26 patients with cardiogenic shock after acute myocardial infarction; randomized to IABP (n = 13) or Impella (n = 12) One patient died before implantation Primary end point of hemodynamic improvement (defined as improved cardiac index at 30 minutes after implantation) was achieved in 25 patients Mean arterial pressure increased more in patients with Impella than in patients with the IABP, but the difference was not significant (P = .09) Improvement in cardiac index significantly greater in Impella patients (P = .02) Diastolic pressure increased significantly more with Impella support than with IABP (P = .002) Use of inotropic agents and vasopressors was similar in both groups of patients Serum level of lactate was lower in patients treated with Impella Hemolysis measured by plasma free hemoglobin was higher in patients treated with Impella (P <.05) More blood products were administered to patients treated with Impella Burzotta et al,11 2008 To evaluate feasibility and long-term safety of Impella-assisted highrisk PCI 10 consecutive patients undergoing elective high-risk PCI All patients had ejection fraction ≤30% and multivessel or left main coronary disease Left ventricular ejection fraction at 6 month followup increased significantly (P = .02) No access site complications No blood products required Ferreiro et al,12 2009 To evaluate the use and safety of the Impella 2.5 in elective high-risk PCI 26 of 30 consecutive patients who underwent high-risk PCI; 3 patients excluded because of cardiogenic shock; 1 excluded because of device malfunction PCI was successfully performed in all patients: • 88.5% remained hemodynamically stable during procedure • 3 patients had severe hypotension develop because of no-reflow • 1 patient died of intracranial hemorrhage 8 hours after the Impella was removed • 3 patients had limb ischemia develop; 1 required surgical intervention • 1 patient had hemolysis develop that required blood transfusion components of the Impella 2.5 catheter include the cable that connects the catheter to the console and a repositioning sheath for bedside repositioning of the Impella 2.5. The components required to run the device are assembled on a Successful placement achieved in all patients No major complications related to the Impella developed in any patients Bleeding developed in 1 patient who required a blood transfusion 2 patients died of causes not related to the Impella rolling cart (Figure 6) and include the power source, the Braun Vista infusion pump, and the Impella console (Figure 7). The Impella console powers the microaxial blood pump and monitors the functioning of the device, including the purge pressure and several other parameters. The console has 10 function keys, but not all of the function keys are used for the Impella 2.5. Some were designed to support future versions of Impella catheters. Function keys that are used with the Impella www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e4 Red pressure sideport Repositioning unit Sideport to hemostasis sheath Plug to console Infusion filter Hemostasis sheath Pressure reservoir Pigtail tip Inlet area Valve to purge fluid Outlet area Blood pump Placement markings on the catheter shaft Figure 2 Components of the Impella 2.5 cardiac assist device. Image courtesy ABIOMED Inc, Danvers, Massachusetts. 2.5 include the P-PERF, MENU, SIGNAL, SCALE, and the ON keys. The console can run on a fully charged battery for up to 1 hour. Figure 3 Blood pump used in the Impella 2.5. Placement of the Device The Impella 2.5 catheter is placed Image courtesy ABIOMED Inc, Danvers, Massapercutaneously through the comchusetts. mon femoral artery and advanced retrograde to the left ventricle over a guidewire. Fluoroscopic guidance in the catheterization Inlet area laboratory or operating room is required. After the device is properly posiMicroaxial blood pump tioned, it is activated and blood is rapidly withOutlet area drawn by the Open pressure area microaxial blood pump from the Figure 4 Detailed view of distal end of Impella 2.5. inlet valve in the Image courtesy ABIOMED Inc, Danvers, Massachusetts. left ventricle and e5 CriticalCareNurse OnlineNOW moved to the aorta via the outlet area, which sits above the aortic valve in the aorta (Figure 8). If the patient tolerates the PCI procedure and hemodynamic instability does not develop, the Impella 2.5 may be removed at the end of the case while the patient is still in the catheterization laboratory. The Impella device can be withdrawn, leaving the arterial sheath in place. The sheath can then be removed later when the patient’s activated clotting time or partial thromboplastin time has returned to near normal levels. For patients who become hemodynamically unstable or who have complications during the PCI (eg, no reflow, hypotension, or lethal arrhythmias), the device can remain in place for continued partial circulatory support, and the patient is transported to the critical care setting. Contraindications The Impella 2.5 cannot be used on all acutely ill patients who require hemodynamic support.14 Because the device is designed to sit across the aortic valve in the left ventricle, it should not be used in patients who have prosthetic aortic valves, so as to prevent damage to the valve. It should not be used in patients with moderate to severe aortic insufficiency; it may worsen the degree of insufficiency because the aortic valve cannot close completely with the device in place. The Impella should not be used in patients with a heavily calcified aortic valve. The device may cause calcium to break off of the aortic valve and embolize, causing stroke. It cannot be used in patients with documented left ventricular thrombus. The impellar www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 Figure 5 Braun Vista infusion pump. Image courtesy ABIOMED Inc, Danvers, Massachusetts. blades of the motor could break up the thrombi, causing arterial embolization. The device also cannot be used in patients with severe peripheral arterial disease because of the large sheath size required for its placement, nor can it be used in patients who cannot tolerate anticoagulation with heparin. Potential Complications of Impella Therapy Figure 6 Rolling cart carrying components required to run the Impella 2.5. Image courtesy ABIOMED Inc, Danvers, Massachusetts. Potential complications of use of the Impella 2.5 are detailed in Table 3. Nursing Care of Patients With an Impella 2.5 for Circulatory Support The nursing care of patients remaining on Impella 2.5 support requires astute assessment and expert nursing care (Table 4). Frequent hemodynamic evaluation is needed. The use of continuous cardiac output monitoring may be useful for patients with cardiogenic shock. Inotropic agents, such as dobutamine and milrinone, and vasopressors, such as dopamine and norepinephrine, may still be needed after the Impella 2.5 is placed to maintain a cardiac index of at least 2 and systolic blood pressure at 90 mm Hg or higher. Some patients on Impella support may be intubated and receiving mechanical ventilation. Implementation of the ventilator The most commonly reported complications of Impella 2.5 placement and support include limb ischemia, vascular injury, and bleeding requiring blood transfusion.6,9 Hemolysis has been reported.5,10 Other potential complications include aortic valve damage, displacement of the distal tip of the device into the aorta, infection, and sepsis. Device failure, although not Figure 7 Console of the Impella 2.5. often reported, Image courtesy ABIOMED Inc, Danvers, Massachusetts. can occur. www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e6 can be mechanically induced when red blood cells are damaged as they pass through the microaxial pump. When hemolysis occurs, hemoglobin level and hematocrit decrease, haptoglobin level decreases, and plasma levels of free hemoglobin increase. If the hemolysis is Figure 8 Fluoroscopic image of Impella 2.5 in place in the aorta. severe, hemogloImage courtesy ABIOMED Inc, Danvers, Massachusetts. binuria will be seen; if the bundle is required for these patients, hemolysis is sustained, acute kidney including elevation of the head of injury will occur. the bed to decrease the risk of Patients on Impella 2.5 support ventilator-associated pneumonia, as who may require interrogation of a well as deep venous thrombosis and permanent pacemaker or implantable peptic ulcer prophylaxis. Regular cardioverter defibrillator present an repositioning of patients and assessinteresting situation. In order for ment of their skin are necessary to the interrogator to connect with the prevent skin breakdown. permanent pacemaker or implantable The patient with an Impella 2.5 cardioverter defibrillator, the Impella is at risk of limb ischemia because of console must be turned off for a few the large size of the device. The arteseconds while the signal is estabrial access site must be assessed reglished. As soon as the signal has ularly for bleeding and development been established, Impella support of a hematoma. Distal pulses of the is immediately restarted. affected leg should be assessed at least hourly. The use of anticoagulation is Impella 2.5 Console required, and bleeding may develop Management in some patients. The partial thromThe recommended maximum boplastin time should be monitored performance level for continuous every 4 to 8 hours and maintained use is P8. At P8, the flow rate is 1.9 at about 45 to 55 seconds, unless a to 2.6 L/min and the motor is turnhigher partial thromboplastin time ing at 50000 revolutions per minute. is required for some other reason. When activated, the console is silent. Hemolysis can occur in patients No sound other than alarms is audiwho are on the Impella 2.5. Hemolysis ble during Impella support, unlike e7 CriticalCareNurse OnlineNOW the sound heard with an IABP. Ten different performance levels ranging from P0 to P9 are available (Table 5). The performance level determines the flow rate and the number of revolutions per minute. As the performance level increases, the flow rate and number of revolutions per minute increase. At maximum performance (P9), the pump rotates at 50000 revolutions per minute and delivers a flow rate of 2.1 to 2.6 L/min. P9 can be activated only for 5-minute intervals when the Impella 2.5 is in use. Several parameters require regular monitoring for the duration of therapy. Regular documentation is essential, and review of trends is useful when troubleshooting. Parameters to assess regularly include placement signal, placement monitoring (pump position), dual signal, purge pressure, motor current, and speed (Table 6). Alarms Several console alarms may require nursing intervention (Table 7). The most common include suction, low purge pressure, and high purge pressure alarms. Information about the alarm can be seen on the console screen. An audible alarm also will sound. Suction alarms can occur if the performance level is too high for the patient; for example, in a patient who is hypovolemic or if the device is emptying the ventricle. A low purge pressure alarm indicates that the purge pressure to the Impella motor has decreased below 300 mm Hg. A low purge pressure can allow blood to enter the motor and damage the motor, rendering the device inoperable. Low purge pressures require www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 Table 3 Potential complications of Impella 2.5 support Complication How it could develop How to recognize Bleeding, vascular injury, ischemia of affected extremity Lack of hemostasis at arterial access site Large sheath (13F) can obstruct/impede flow to affected extremity Direct arterial damage can occur during device placement Loss of pulses in affected foot/leg Pain, pallor, coolness, paresthesia, and/or paralysis of affected foot/leg Decreased hemoglobin and hematocrit Assess and monitor pulses, skin color, temperature, and capillary refill hourly Notify physician of changes to the affected extremity Monitor results of laboratory tests Administer blood and blood products as ordered Hemolysis Rupture of red blood cells by impellar blades/high flow causing hemoglobin to leak into plasma Laboratory specimens are hemolysed Urine is red, burgundy, brown because of red blood cells in the urine Decreased haptoglobin levels, elevated plasma levels of free hemoglobin Hemolysis is most pronounced when Impella is not positioned well; notify physician of hemolysis Anticipate echocardiography to assess repositioning of Impella Decrease flow levels on Impella when possible Device migration Catheter may inadvertently advance or be withdrawn with excessive movement, turning Positioning alarms Changes in placement signal parameters Maintain elevation of head of bed at ≤30° After placement, note position markings on catheter shaft and document for reference each shift Secure device with tape; secure tubings to lower leg Infection, sepsis Placement of Impella and other invasive monitoring catheters Inflammation, tenderness, or purulent drainage at access site Increased body temperature Aseptic technique during placement Sterile dressing change Daily tubing change Monitor patient for fever, elevated white blood cell count Aortic valve damage (rare) Trauma during device placement Continued heart failure due to aortic valve damage Echocardiographic evidence of aortic insufficiency Monitor placement signal hourly Notify physician of Impella position alarms Device failure (rare) Defective device Loss of pump function, console alarms Deterioration in patient’s condition Monitor and document console parameters hourly Respond promptly to console alarms and trouble-shoot as indicated Notify Impella coordinator and physician of ongoing alarms immediate intervention by a critical care nurse. A high purge pressure alarm indicates that the purge pressure is greater than 700 mm Hg and generally indicates a kink in the tubing or catheter. If the device advances too far and both the inflow and outflow areas are fully in the left ventricle, the pump position wrong alarm will occur. On the placement signal screen, the waveform will show a ventricular, rather than an aortic, pressure waveform. How to prevent/manage The motor current signal will be flattened. The placement monitoring diagram will show the aortic valve symbols distal to the pump (Figure 9). The performance level should be decreased to P2 and the physician should be notified to reposition the device by pulling it back slightly to obtain an aortic waveform. Repositioning is best performed under fluoroscopic guidance, whenever possible. If the Impella 2.5 is completely in the aorta, or if the inlet and outlet areas are in the ventricle and the pressure port is in the aorta, the pump position alarm will sound. The placement signal will show a normal appearing aortic waveform with systolic and diastolic pressures similar to those shown by the patient’s arterial catheter. The motor current will be flattened. The placement monitoring diagram will continuously scroll through 3 different images because it is not able to differentiate the position of the catheter. www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e8 Table 4 Nursing care of patients with an Impella 2.5 Problem Expected outcomes/goals Nursing intervention and rationale Decreased cardiac output related to decreased cardiac contractility With the Impella in place, the patient will • be hemodynamically stable, as evidenced by systolic blood pressure >90 mm Hg, heart rate >50/min and <100/min, cardiac indexa ≥2 • have warm and dry skin • maintain urine output >30 mL/h • be alert and oriented • be free of hemodynamically compromising arrhythmias Continuous cardiac monitoring Measure vital signs and pulmonary artery pressures hourly; notify physician of changes Determine cardiac output/cardiac index every 4 hours and with changes in vasoactive medications; notify physician of changes Administer and titrate vasoactive medications as ordered Monitor urine output hourly and notify physician if <30 mL/h Evaluate for changes in mental status, including confusion, restlessness, and decreased responsiveness If patient requires cardiopulmonary resuscitation, decrease Impella performance level to P2 for duration of chest compressions; after chest compressions, obtain chest radiograph or echocardiogram to assess placement of the Impella Potential for bleeding related to device placement and anticoagulation The patient will: • be free of bleeding/hematoma at the arterial access site • have a partial thromboplastin time (PTT) between 45 and 55 seconds • maintain baseline hemoglobin, hematocrit, and platelet levels Assess the arterial access site for bleeding/hematoma hourly Adjust heparin infusion as needed to maintain PTT parameters; measure PTT every 6-8 hours while on Impella support Notify physician of PTT outside of goal range and titrate heparin infusion as needed Assess laboratory results, including hemoglobin level, hematocrit, and platelet count Notify physician of decreases in hemoglobin level, hematocrit, or platelet count Potential for limb ischemia due to device placement Patient will • maintain baseline circulation to affected extremity Monitor presence and quality of distal pulses in the affected extremity hourly Assess sensation and movement of affected extremity Notify physician of loss of pulses, pallor, pain in leg/foot, loss of sensation/movement Potential for hemolysis related to device placement Patient will • maintain integrity of red blood cells • maintain urine free of red blood cells Monitor laboratory samples for presence of hemolysis Monitor plasma levels of free hemoglobin and haptoglobin Monitor urine for changes in color, as hemolysis breaks down red blood cells, urine becomes red to brown Administer blood and blood products as ordered Potential for infection related to device placement Patient will • remain free of signs and symptoms of infection Change sterile dressing daily by using strict aseptic technique; change more frequently if any drainage is present Remove monitoring catheters as possible Ensure adequate nutrition to promote healing Notify physician of elevated body temperature and other signs of infections, such as redness, tenderness, warmth at the site, purulent drainage, elevated white blood cell count Potential for device malfunction/device failure Patient will • be free of device failure Elevate head of bed ≤30°, turn patient carefully to prevent inadvertent pulling on the Impella catheter shaft and/or tubing Assess and document exposed number of centimeter markings on the catheter shaft once each shift Assess and troubleshoot positioning alarms (outlined in Table 7) Notify physician of suspected suboptimal positioning of device or device failure immediately Potential for discomfort related to pain, anxiety, bed rest Patient will • be comfortable • report decreased anxiety Administer analgesics as ordered for discomfort Reposition patient for comfort as needed Knowledge deficit Patient/patient’s family will • verbalize understanding of plan of care and need for device Explain the need for the Impella device in assisting the heart Help the patient and the patient’s family understand the need for bed rest, careful repositioning, frequent assessment, and daily tubing and dressing changes a Calculated as cardiac output in liters per minute divided by body surface area in square meters. e9 CriticalCareNurse OnlineNOW www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 rapid weaning can be done. For rapid weanPerformance level Flow rate, L/min Revolutions per minute ing, the perP0 0.0 0 formance level P1 0.0-0.5 25 000 is decreased by P2 0.4-1.0 35 000 1 or 2 levels P3 0.7-1.3 37 000 every 5 to 15 P4 0.9-1.5 40 000 minutes until P5 1.2-1.8 43 000 the pump is P6 1.4-2.0 45 000 set at P2. The P7 1.6-2.2 47 000 patient’s hemoP8a 1.9-2.5 50 000 dynamic status P9b 2.1-2.6 51 000 is assessed after every decrease a Level P8 is recommended maximum performance for continuous use. b P9 is used for verification of catheter position only—can also be used to proin performance vide maximum flow for up to 2 minutes (console will automatically default to P8 level. P2 is the after 5 minutes). lowest performance level that The performance level should be can be used while the distal end of reduced to P2 and the physician the Impella 2.5 is in the left ventrishould be notified of the need to cle. At the end of rapid weaning, reposition the Impella. the Impella device can then be If the patient’s ventricular funcremoved as described in the next tion is very poor, a positioning alarm section. can occur. The alarm will read “pump Patients who have had the device position unknown due to low pulin longer or who were in unstable satility.” The Impella console is not condition during the procedure able to determine the pump posimay benefit from a slower weaning tion because the patient’s systolic process. Slow weaning is accomand diastolic pressures are not very plished by decreasing the performdifferent. The placement signal will ance level by 1 or 2 levels every 2 or show depressed cardiac function, 3 hours. If the patient tolerates this evidenced by a damped appearing slow weaning by remaining hemowaveform. The motor current will dynamically stable while at P2, the be flattened. The aortic valve symbols device is then removed. will not be seen on the placement In our facility, we often use monitoring diagram. transthoracic echocardiography to aid in the assessment of our patients. Weaning With the physician at the bedside, Weaning from the partial circulatransthoracic echocardiography is tory support provided by the Impella performed and the pump’s perform2.5 can be approached in different ance level is decreased. The physiways. When the device has been in cian can evaluate left ventricular only for support during high-risk PCI size and function and can quickly and the patient’s condition is stable assess how well the patient tolerates after the procedure is completed, decreases in the performance level. Table 5 Impella 2.5 performance level and flow rate Device Removal When the physician is ready to discontinue the Impella 2.5 catheter, the groin dressing should be removed, the site cleansed with chloroprep, and the sutures clipped. Immediately before removal of the device, decrease the performance level to P0. The catheter is then pulled back from the left ventricle into the ascending aorta and then completely withdrawn. The arterial sheath can be left in place to be removed separately, or the catheter and the sheath can be removed as a unit, as is common when removing an intra-aortic balloon catheter placed through a sheath. The Impella 2.5 instructions for use recommend a 40-minute manual hold to achieve hemostasis at the arterial access site. We follow our hospital’s protocol for achieving hemostasis, using either manual or mechanical compression. Some facilities may use what is referred to as a preclose method while the patient is still in the catheterization laboratory; that technique uses 2 8F Perclose suture-mediated closure devices (Abbott Laboratories, Abbott Park, Illinois). The Impella 2.5 can also be removed in the surgical setting with direct visualization of the common femoral artery. A cutdown is performed, and the device is removed by the surgeon. Arterial repair is done at that time, and the incision is covered with a sterile dressing. Our Experience To date, we have placed an Impella 2.5 in about 40 patients. Our facility has a high-volume interventional cardiology program as well as a busy adult and pediatric www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e10 Table 6 Console monitoring screens Parameter What it means Placement signal This is a positioning aid. It evaluates the position of the device. The pressure is obtained from the pressure lumen that ends near the motor. It should “see” an aortic waveform; however, if the device is too far in, a ventricular waveform will be seen. Motor current Displays the amount of electrical current that is required to power the motor of the catheter device. The motor current increases as the flow increases and decreases as the flow decreases. It should be a pulsatile waveform. Purge pressure Displays the current purge pressure. This pressure is measured in millimeters mercury (mm Hg). Speed Displays the rotations per minute of the impellar blades. Flow Displays the flow that is being aspirated from the left ventricle. This value can be found in the upper right corner of all screens. Screen display This graphic display shows a Placement monitoring schematic of the pump position in relationship to the aortic valve. Dual signal Displays 2 waveforms. The top waveform is the motor current and the bottom waveform is the placement signal. This screen can be useful in advanced troubleshooting. cardiovascular surgery service. We have extensive experience with the IABP and with surgically placed VADs, including the Abiomed AB5000, Thoratec CentriMag, XVE, and HeartMate II. Our use of the Impella 2.5 was our first experience with percutaneously placed partial circulatory support devices. We have also placed the Impella 5.0 in e11 CriticalCareNurse OnlineNOW 3 patients. We have gained much knowledge since implementing our Impella program in April 2008. Based on our experiences, we share the following recommendations. 1. Assign a point person who can oversee and coordinate the program. In our facility, this role is filled by the interventional cardiology clinical nurse specialist. All patients with this device are observed by this clinical nurse specialist during their hospital stay. Additionally, patients are observed by the VAD coordinator. 2. Limit the physicians who can place and manage the device and have them proctor one another. In our facility, physicians who can place this device are those who have interventional cardiology and/or cardiac surgery privileges. All cases are also followed by the cardiac surgeon who oversees our VAD program and a critical care intensivist. We developed preprinted orders for physicians to use for patients remaining on support to ensure consistency in care (Table 8). 3. Train a core group of nurses and cardiovascular technologists from the catheterization laboratory for initial setup of the console, catheter preparation, and assisting with placement of the device. Console and infusion pump setup requires 2 to 3 minutes to complete. Our training for staff from the catheterization laboratory consisted of a 3-hour session with didactic and hands-on training. Ongoing practice is essential to develop and maintain competency. The Impella coordinator is present for implants to assist the catheterization laboratory staff as needed. The VAD coordinators also provide valuable assistance. We found it helpful for the first few Impella placements to be planned, elective placements for high-risk PCI. This arrangement allowed ample time for setting up the console and infusion pump before the Impella was placed. 4. Develop a nursing protocol that outlines key strategies in patient www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 Table 7 Impella 2.5 alarm troubleshooting Alarm What to do What it means Low purge pressure Purge pressure is less than 300 mm Hg. Correct the purge pressure quickly to prevent damage of the motor With low purge pressure, blood can Assess for leaks or loose connections in the purge system. enter the motor and damage it. Increase the purge pressure by delivering a bolus of 1 mL and increasing the continuous rate on the Braun Vista Pump by 1 mL/h. If maneuvers to increase the purge pressure to between 300 and 700 mm Hg are not effective within 5 minutes, the Impella may need to be removed. High purge pressure Purge pressure is higher than 700 mm Hg. Tubing may be kinked. Concentration of purge fluid may be too high. Suction likely The console has detected pump suction. Reduce the performance level by 2 levels (for example, decrease from P8 to P6). The patient may be hypovolemic, and the pump may be completely empty- Assess hemodynamics and left ventricular filling; correct hypovolemia if present. ing the left ventricle. Pump position wrong Pump outlet is blocked—the pump is too far in the ventricle and the outlet may be at the level of the aortic valve. Reposition pump; wrong pump position was detected. Assess and support patient as indicated. Notify the physician/Impella coordinator. May assess placement by echocardiography/portable chest radiography. Pump most likely needs to be repositioned by the physician. High motor current value There are mechanical problems with the pump. The motor current for the selected performance level has been exceeded. If the motor current continues to increase, the catheter should be removed. Look for kinks in the tubing or catheter. Decrease the flow rate of purge fluid by 1 mL/h on the Braun Vista Pump. Do not decrease the flow rate to less than 4 mL/h. May need to decrease the concentration of the purge fluid (eg, change from 20% dextrose to 10% dextrose). If the alarm persists for more than 2 hours after the preceding steps are taken, the device should be removed. Figure 9 Placement monitoring screen display shows that pump position is wrong. Image courtesy ABIOMED Inc, Danvers, Massachusetts. management and a specific flow sheet (Figure 10) for documentation. 5. Train a core group of critical care nurses to care for the patient, monitor the device, change tubings, and troubleshoot alarms. We provide 1-to-1 staffing for our patients with an Impella 2.5 until they are hemodynamically stable. Our training for our cardiac intensive care unit (CICU) nurses consisted of a series of three 1-hour sessions, encompassing a review of pertinent physiology and hemodynamics, Impella console management and troubleshooting, and tubing changes with hands-on practice and documentation practice. Staff received 1-to-1 mentoring from the Impella coordinator. Review of patient care www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e12 Table 8 Physician orders for placement of Impella 2.5 Transfer to cardiac intensive care unit, continuous cardiac monitoring See orders for after percutaneous coronary intervention for additional physician orders Complete bed rest; may turn and reposition patient as needed; do not elevate head of bed to >30° Every hour and as needed: assess and document patient’s vital signs, access site, distal pulses, hemodynamic parameters, urine output, Impella performance level, flow, placement signal, motor current, pump position, and purge pressure Perform the following diagnostic tests: On arrival in unit: complete blood cell count, renal panel, partial thromboplastin time, plasma free hemoglobin, portable chest radiograph, 12-lead electrocardiogram Every 8 hours while on Impella support: partial thromboplastin time In morning: transthoracic echocardiography to assess placement of device Daily while on Impella support: plasma-free hemoglobin, complete blood cell count, renal panel Notify Impella coordinator of changes in patient’s status or concerns regarding Impella device/Impella console Notify physician if partial thromboplastin time <45 seconds; goal for partial thromboplastin time is 45-55 seconds Daily at 3 PM: Change purge fluid/tubing system by using 500 mL dextrose 20% in water with heparin 25 000 units Change arterial fluid/tubing system, using 500 mL normal saline with heparin 1000 units Sterile dressing change management strategies, console troubleshooting, and fluid/tubing setup has also been added to our annual VAD skills fair (Table 9). 6. Work with pharmacy and nursing staff to develop a standardized time for fluid and tubing changes. We found performing such changes at a consistent time to be very helpful. This arrangement ensured that new purge fluid was ready when needed and that the nurses had more staffing resources to assist with the tubing change. The pharmacy prepares the heparinized 20% glucose purge solution and sends it to the unit before our standard change time of 3 PM daily. We have 2 nurses at the bedside for the tubing change. The Impella coordinator is present to assist with tubing changes as needed by the nursing staff. 7. Include the cardiovascular surgery staff and perfusion staff in the e13 CriticalCareNurse OnlineNOW initial training. Patients with an Impella may go to the cardiovascular operating room for bypass surgery or valve repair/replacement. Coordination with the perfusionist is essential when patients are being placed on cardiopulmonary bypass. As the patient goes on cardiopulmonary bypass, the performance level of the Impella must be decreased. When the patient is coming off of cardiopulmonary bypass, the performance level of the Impella pump, if the pump remains in place, must be increased to provide adequate flow to the patient. In some facilities, the perfusionist manages both the cardiopulmonary bypass and the Impella. In our facility, we have a trained CICU nurse managing the Impella while the patient is in the cardiovascular operating room. 8. Partner with industry. Abiomed provides strong clinical support as well as excellent print and Web-based educational materials. A console simulator is available that can be used to practice troubleshooting. Abiomed also provides assistance with troubleshooting via 24-hour-a-day, 7-day-a-week telephone support. Summary The Impella 2.5 device is an alternative to an IABP that may be beneficial in some patients who need hemodynamic support. It is useful in patients undergoing highrisk PCIs. The Impella 2.5 should not be used in patients with aortic valve disease or known left ventricular thrombus. Potential complications include bleeding, vascular injury, hemolysis, infection, sepsis, and device malfunction or failure. Nursing care is directed toward support of critically ill patients, including frequent hemodynamic assessment, titration of vasoactive medications as indicated, Impella console troubleshooting, and monitoring for potential complications. A multidisciplinary approach to establishing a program for the Impella is useful in ensuring competency and good outcomes for patients. The following 3 case studies demonstrate the successful use of Impella 2.5 support during highrisk PCIs at our facility. Case Study 1 A 71-year-old man was referred to our facility for saphenous vein bypass graft (SVG), a high-risk PCI. Diagnostic cardiac catheterization and coronary angiography performed at the referring facility showed severe triple vessel coronary disease and high-grade lesions in 2 SVGs. He had a history of coronary www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 Date: ___________________________ ABIOMED 1-800-422-8666 Time: Infusion Rate (mL) (4-12 mL) Flow L/min: P-Perf Level: Placement Signal: Pump Position: Dual Signal: Purge Pressure: (300-700-mmHg) Motor Current: Speed RPM: Power (AC / Batt): Groin Check (✓) Pulse Check (✓) Initials Patient Identification Document hourly and PRN RN SIGNATURE Every 8 hour labs: creatinie, ABGs with ionized calcium, PTT Notify physician if PTT < 45 seconds Ventricular Assist Device Flowsheet for Impella 2.5 21781 (5/13/09) FLOWSHEET Pump Serial Number: Access Site: Right / Left Femoral Artery # of exposed Hash Marks: Last sterile dressing change: Last tubing change: Use back of flow sheet for additional Impella documentation id needed Figure 10 Impella 2.5 flowsheet. Abbreviations: ABGs, arterial blood gas analysis; AC, alternating current; Batt, battery; P-perf, pump performance level; PRN, as needed; PTT, partial thromboplastin time; RN, registered nurse; RPM, revolutions per minute. Image courtesy Sutter Medical Center, Sacramento, California. artery bypass grafting surgery several years prior as well as heart failure. His estimated ejection fraction was markedly decreased at 20% (normal, 55%-70%) on a recent echocardiogram. He was experiencing progression of his anginal symptoms, and his functional capacity was poor. He declined repeat bypass surgery. After careful evaluation and optimization of pharmacological therapy for heart failure, the decision was made to proceed with high-risk PCI of the SVG to the left anterior descending (LAD) artery with an Impella 2.5 used to provide partial circulatory support during the PCI. The patient was brought to the catheterization laboratory and prepared for the procedure. On arrival, his blood pressure was 151/88 mm Hg with a heart rate of 66/min. Sheaths were placed in the right femoral vein, the right femoral artery, and the left femoral artery. An SvO2 pulmonary artery catheter showed that the patient’s baseline pulmonary artery pressures were markedly elevated at 69/40-47 mm Hg (normal: 20-30/8-12 mm Hg; mean, 25 mm Hg). Heparin 7000 units was administered intravenously for anticoagulation. When the activated clotting time was higher than 250 seconds, the Impella 2.5 was advanced into position via the left common femoral artery and placed across the aortic valve into the left ventricle. The catheter device was connected to the Impella console and support was initiated. The performance level was increased from P0 to a maximum of P8 in a matter of minutes. At P8, the flow was 2.5 L/min and the patient’s cardiac index was 2.58 (normal, 2.5-4). The PCI procedure of the LAD SVG was then started. The SVG was aspirated before a distal protection device was placed. One bare metal stent (not a drug eluting stent) was www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e14 Table 9 Impella competency checklist for nurses in the cardiac intensive care unit: critical elements for managing patients with an Impella 2.5 Lists resources for assistance (trained peers, clinical nurse specialists, ventricular assist device coordinators, ABIOMED toll-free phone line, reference binder on Impella cart) Demonstrates use of Impella console: Verifies placement signal Changes performance level/pump speed Verifies purge pressure Demonstrates troubleshooting of Impella components: Power supply Common alarms (low and high purge pressure, suction) Braun Vista infusion pump discharged 2 days later taking appropriate medications for after PCI and to treat heart failure. Six weeks later, the patient was pain free with no complaints of dyspnea. Transthoracic echocardiography showed increased contractility, and the ejection fraction was 40%. At follow-up 12 months later, the patient remained symptom-free with a normal ejection fraction of 55%. Changes arterial flush fluid and tubing per checklist Changes purge fluid and tubing per checklist Case Study 2 Describes required patient care Assessment/reassessment of findings, including hemodynamic profile Performs sterile dressing change States potential complications and how to assess/prevent them Reviews orders, communicates changes to cardiology/cardiothoracic surgeon If cardiopulmonary resuscitation needed, decrease performance level to P2, and initiate Advanced Cardiac Life Support protocols A 74-year-old man was transferred to our facility after sustaining a non–ST-segment elevation myocardial infarction. He had a long history of diabetes and had undergone coronary artery bypass surgery 20 years prior. Diagnostic cardiac catheterization showed severe triple vessel disease as well as severe diffuse distal disease of his left internal mammary artery (LIMA) graft, his only remaining patent graft. He had severe mitral regurgitation. His ventricular function was poor with a calculated ejection fraction of 20%. His left ventricular end-diastolic pressure was markedly elevated at 40 mm Hg (normal, 5-12 mm Hg), and his cardiac index was reduced at 1.98. He was evaluated by our cardiothoracic surgery team and was deemed an extremely poor candidate for surgery. After a family conference that included the patient, the decision was made to proceed with high-risk PCI of the LIMA graft, using the Impella 2.5 for hemodynamic support during the procedure. He returned to the catheterization laboratory the next day for coronary intervention. On arrival, his blood pressure was 105/66 mm Hg with a heart rate of 64/min. Sheaths placed in the SVG to the LAD. During this time, transient no-reflow developed. No reflow is a phenomenon in PCI that can cause severe hemodynamic compromise because myocardial perfusion through a given segment of the coronary circulation is inadequate, yet no angiographic evidence of mechanical obstruction of the vessel is apparent.15 The patient’s pulmonary artery pressures increased to 93/40-58 mm Hg and the cardiac index decreased to 2.2. Despite the no-reflow, the arterial pressure, heart rate, and cardiac rhythm remained stable, and the patient had no complaints of shortness of breath or chest discomfort. Adequate blood flow was reestablished after the intracoronary administration of 500 µg nitroglycerin. Because the patient was tolerating the procedure well after this, the physician decided to stent the second diseased SVG. With the Impella continuing at maximum flow of 2.5 L, 2 bare metal stents were deployed e15 CriticalCareNurse OnlineNOW in the SVG to the posterior lateral branch. Pulmonary artery pressures remained elevated after this stent was placed, and the patient was given furosemide and nitroglycerin to decrease preload and increase diuresis. Just before the patient’s return to the CICU, the pulmonary artery pressure decreased to 70/4148 mm Hg and the cardiac index was 2.69. The patient was weaned from the Impella device, the device was removed in the catheterization laboratory, and the venous and arterial sheaths were secured in place. The total duration of Impella support was slightly less than 2 hours. The patient was transferred to the CICU for continued monitoring. Four hours later, after the activated clotting time was less than 150 seconds, the venous and arterial sheaths were removed and hemostasis was achieved after 40 minutes of manual compression. The patient’s remaining hospital course was uneventful and he was www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 were placed in the right femoral vein, the right femoral artery, and the left femoral artery. Heparin 9000 units was administered intravenously for anticoagulation, and the Impella 2.5 was advanced into position in the left femoral artery. Support was established at P8. The coronary guidewire was advanced through the LIMA graft to the distal LAD. Three sequential stents were placed in the area of disease. The patient’s vital signs and cardiac rhythm remained stable throughout the procedure. The patient was rapidly weaned from the Impella, which was removed in the catheterization laboratory. The 13F arterial sheath was sutured in placed for removal 4 hours later after the patient was returned to the CICU. He was discharged home 2 days later. Case Study 3 A 63-year-old woman was admitted to our facility with an acute anteroseptal myocardial infarction. She was treated with fibrinolytic therapy but continued to have chest pain. She had a history of hypertension complicated by end-stage renal disease and was receiving dialysis treatments 3 times per week. She was taken to the catheterization laboratory, where she was found to have a significant obstruction of the left main coronary artery complicated by plaque rupture. She was evaluated by our cardiac surgery team, who thought that she was a very highrisk candidate for surgery based on the recent fibrinolytic therapy, her renal failure, and the remote history of stroke. She was transferred to the CICU and supportive medical therapy was initiated. She returned to the catheterization laboratory 3 days later for highrisk PCI of the left main coronary artery. On arrival, her blood pressure was 127/72 mm Hg, and her heart rate was 54/min. Sheaths were placed in the right femoral vein, the right femoral artery, and the left femoral artery. Bivalirudin was administered for anticoagulation, and the Impella 2.5 was advanced into position in the left femoral artery. Support was established at P8. The left main lesion was crossed, and one stent was deployed at the lesion. During stent deployment, the patient had severe chest pain and showed ST-segment elevation in the anterior leads. Despite these changes, her blood pressure and cardiac rhythm remained stable. Intravascular ultrasound was performed to confirm optimal stent placement. At the end of the procedure, she was symptom free, and she was rapidly weaned from the Impella and the device was removed. The 13F arterial sheath was sutured in placed for removal 2 hours later, after the patient had returned to the CICU. She had no further chest pain during her hospitalization and was discharged home in stable condition 3 days later. CCN 3. Lee MS, Makkar RR. Percutaneous left ventricular support devices. Cardiol Clin. 2006;24(2):265-275. 4. Kale P, Fang JC. Devices in acute heart failure. Crit Care Med. 2008;36(suppl):S121-S128. 5. Seyfarth M, Sibbing D, Bauer I, et al. A randomized clinical trial to evaluate the safety and efficacy of a percutaneous left ventricular assist device versus intra-aortic balloon pumping for treatment of cardiogenic shock caused by myocardial infarction. J Am Coll Cardiol. 2008;52:1584-1588. 6. Remmelink M, Sjauw KD, Henriques JP, et al. Effects of left ventricular unloading by Impella Recover LP 2.5 on coronary hemodynamics. Catheter Cardiovasc Interv. 2007; 70(4):532-537. 7. Reid MB, Cottrell D. Nursing care of patients receiving intra-aortic balloon counterpulsation. Crit Care Nurse. 2005;25(5):40-49. 8. Weber DM, Raess DH, Henriques JPS, Siess T. Principles of Impella cardiac support. http:// bmctoday.net/citoday/2009/09/supplement /article.asp?f=0909_supp_01.php. Accessed November 16, 2010. 9. Henriques JPS, Remmelink M, Baan J, et al. Safety and feasibility of elective high-risk percutaneous coronary intervention procedures with left ventricular support of the Impella Recover LP 2.5. Am J Cardiol. 2006; 97(7):990-992. 10. Dixon SR, Henriques JPS, Mauri L, et al. A prospective feasibility trial investigating the use of the Impella 2.5 system in patients undergoing high-risk percutaneous coronary intervention (the PROTECT I trial): Initial U.S. experience. J Am Coll Cardiol. 2009;2:91-96. 11. Burzotta F, Paloscia L, Trani C, et al. Feasibility and long-term safety of elective Impella-assisted high-risk percutaneous coronary intervention: a pilot two-centre study. J Cardiovasc Med. 2008;9:1004-1010. 12. Ferreiro JL, Gomez-Hospital JA, Cequier AR, et al. Use of Impella Recover LP 2.5 in elective high risk percutaneous coronary intervention [published online ahead of print September 2, 2009]. Int J Cardiol. doi:10.1016/j.ijcard.2009.08.003. 13. Stahl MA, Richards NM. Update on ventricular assist device technology. AACN Adv Crit Care. 2009;20(1):26-34. 14. Impella: Instructions for Use for the Impella 2.5 Circulatory Support System. Danvers, MA: Abiomed, Inc; 2007. 15. Eeckhout E, Kern MJ. The coronary no-reflow phenomenon: a review of mechanisms and therapies. Eur Heart J. 2001;22:729-739. Now that you’ve read the article, create or contribute to an online discussion about this topic using eLetters. Just visit www.ccnonline.org and click “Respond to This Article” in either the full-text or PDF view of the article. Financial Disclosures Brenda McCulloch is a member of the Abiomed Administrative Advisory Board. References 1. Vegas A. Assisting the failing heart. Anesthesiol Clin. 2008;26:539-564. 2. Sarkar K, Kini AS. Percutaneous left ventricular support devices. Cardiol Clin. 2010;28:169-184. www.ccnonline.org Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014 CriticalCareNurse OnlineNOW e16 Downloaded from http://ccn.aacnjournals.org/ by guest on June 9, 2014